Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
C++ Bresenham 3d Line Drawing Algorithm
// Bresenham3D
//
// A slightly modified version of the source found at
// http://www.ict.griffith.edu.au/anthony/info/graphics/bresenham.procs
// Provided by Anthony Thyssen, though he does not take credit for the original implementation
//
// It is highly likely that the original Author was Bob Pendelton, as referenced here
//
// ftp://ftp.isc.org/pub/usenet/comp.sources.unix/volume26/line3d
//
// line3d was dervied from DigitalLine.c published as "Digital Line Drawing"
// by Paul Heckbert from "Graphics Gems", Academic Press, 1990
//
// 3D modifications by Bob Pendleton. The original source code was in the public
// domain, the author of the 3D version places his modifications in the
// public domain as well.
//
// line3d uses Bresenham's algorithm to generate the 3 dimensional points on a
// line from (x1, y1, z1) to (x2, y2, z2)
//
void Bresenham3D(int x1, int y1, int z1, const int x2, const int y2, const int z2, WorldMap *output, int symbol){
int i, dx, dy, dz, l, m, n, x_inc, y_inc, z_inc, err_1, err_2, dx2, dy2, dz2;
int point[3];
point[0] = x1;
point[1] = y1;
point[2] = z1;
dx = x2 - x1;
dy = y2 - y1;
dz = z2 - z1;
x_inc = (dx < 0) ? -1 : 1;
l = abs(dx);
y_inc = (dy < 0) ? -1 : 1;
m = abs(dy);
z_inc = (dz < 0) ? -1 : 1;
n = abs(dz);
dx2 = l << 1;
dy2 = m << 1;
dz2 = n << 1;
if ((l >= m) && (l >= n)) {
err_1 = dy2 - l;
err_2 = dz2 - l;
for (i = 0; i < l; i++) {
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol);
if (err_1 > 0) {
point[1] += y_inc;
err_1 -= dx2;
}
if (err_2 > 0) {
point[2] += z_inc;
err_2 -= dx2;
}
err_1 += dy2;
err_2 += dz2;
point[0] += x_inc;
}
} else if ((m >= l) && (m >= n)) {
err_1 = dx2 - m;
err_2 = dz2 - m;
for (i = 0; i < m; i++) {
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol);
if (err_1 > 0) {
point[0] += x_inc;
err_1 -= dy2;
}
if (err_2 > 0) {
point[2] += z_inc;
err_2 -= dy2;
}
err_1 += dx2;
err_2 += dz2;
point[1] += y_inc;
}
} else {
err_1 = dy2 - n;
err_2 = dx2 - n;
for (i = 0; i < n; i++) {
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol);
if (err_1 > 0) {
point[1] += y_inc;
err_1 -= dz2;
}
if (err_2 > 0) {
point[0] += x_inc;
err_2 -= dz2;
}
err_1 += dy2;
err_2 += dx2;
point[2] += z_inc;
}
}
output->getTileAt(point[0], point[1], point[2])->setSymbol(symbol);
}
@sriharsha48

This comment has been minimized.

Copy link

sriharsha48 commented Dec 11, 2017

Hi,What if my coordinates x1.y1,z1 are of type ;double',then I am getting this : error C2296: '<<' : illegal, left operand has type 'double'
Can you please explain the way to rectify this error.

Also,if I want to use for a size of some 0.3 or 0.5,I want to fix one paramter 'resolution',Which can have any value like 0.3 or 0.5 or 1.
I think,your code only works for a grid size of 1,right?

@Modanung

This comment has been minimized.

Copy link

Modanung commented Dec 18, 2017

@sriharsha48 That's what the Bresenham's line algorithm is all about; drawing a line on a grid. From Wikipedia:

Bresenham's line algorithm is an algorithm that determines the points of an n-dimensional raster that should be selected in order to form a close approximation to a straight line between two points.

It it supposed to only work with integer values... now, let's give it a try. :)

@Modanung

This comment has been minimized.

Copy link

Modanung commented Dec 18, 2017

Seems to be working great! Many thanks @yamamushi!

image

If anyone's interested, the screenshot is from a level editor I'm working on called Edddy.

@yamamushi

This comment has been minimized.

Copy link
Owner Author

yamamushi commented Jan 18, 2018

@Modanung glad you found it useful! Your level editor looks awesome by the way :)

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.